oprG encodes an outer membrane protein of the OmpW family, an eight-stranded beta-barrel with a cleavable signal peptide that is abundant in the outer membrane under anaerobic, iron-rich conditions, where its transcription depends on the ANR regulator. Purified OprG forms cation-selective channels in planar lipid bilayers, and in reconstituted liposomes and growth assays it allows the passage of small amino acids such as glycine, alanine, valine and serine, with the dynamics of its extracellular loops important for transport. It does not appear to mediate iron or antibiotic uptake. Loss of OprG reduces the cytotoxicity of P. aeruginosa toward human bronchial epithelial cells.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0016020 membrane | IBA GO_REF:0000033 | MODIFY | Summary: PAINT IBA to generic membrane from E. coli OmpW (P0A915). Reason: Correct but general. OprG is a signal-peptide-bearing beta-barrel described as a major outer membrane protein, and its family is the OmpW outer membrane protein family; the specific location is GO:0009279 cell outer membrane. Propagation Review Root cause: NO FAILURE CORE Failure modes: GRANULARITY MISMATCH Sources checked: UniProtKB:P0A915 Β· ompW (E. coli) SUPPORTS TRANSFER E. coli OmpW is an outer membrane protein; the IBD stops at generic membrane, which is true but less specific than the family warrants. Proposed replacements: cell outer membrane Supporting Evidence: PMID:21124774 OprG forms an eight-stranded Ξ²-barrel with a hydrophobic channel that leads from the extracellular surface to a lateral opening in the barrel wall. PMID:19486157 OprG of Pseudomonas aeruginosa is a member of the very large and widely distributed but poorly characterized OmpW (PF0392) family of outer membrane proteins. |
| GO:0019867 outer membrane | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO from the OmpW family. Reason: Correct but general; GO:0019867 also covers organelle outer membranes. The bacterial term is GO:0009279 cell outer membrane. Proposed replacements: cell outer membrane Supporting Evidence: PMID:19486157 OprG of Pseudomonas aeruginosa is a member of the very large and widely distributed but poorly characterized OmpW (PF0392) family of outer membrane proteins. |
| GO:0044384 host outer membrane | IEA GO_REF:0000002 | REMOVE | Summary: InterPro2GO from IPR000758 (enterobacterial virulence OMP signature) to host outer membrane. Reason: GO:0044384 is the outer membrane of a host cell. OprG is in the outer membrane of P. aeruginosa itself and is not delivered into host cells; the InterPro2GO mapping of IPR000758 to a host term is wrong for a bacterial outer membrane protein. Supporting Evidence: PMID:26655471 OprG is an outer membrane protein of Pseudomonas aeruginosa whose function as an antibiotic-sensitive porin has been controversial and not well defined. |
| GO:0055085 transmembrane transport | IBA GO_REF:0000033 | MODIFY | Summary: PAINT IBA from PTN005107949, whose sole seed is this gene's PseudoCAP IDA (PMID:19486157). Sound for the OmpW clade; for OprG itself more specific transport is shown. Reason: The generic term is a good choice at the family node, whose members' substrates are poorly known. For OprG the supported processes are amino acid transmembrane transport (liposome swelling and growth assays) and monoatomic cation transmembrane transport (cation-selective channel), both descendants of GO:0055085. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN005107949 Β· PTN005107949 SUPPORTS TRANSFER QuickGO (2026-10-28) lists 13 GO:0055085 IBA leaves, mostly bacterial OmpW proteins (E. coli P0A915, Salmonella, Vibrio, Shewanella, Yersinia, Xanthomonas, Bradyrhizobium). Two eukaryotic genome entries (Medicago A0A072TCN1, Nematostella A8DW24) are probably bacterial contaminants and their IBAs are doubtful. UniProtKB:Q9HWW1 Β· oprG SUPPORTS TRANSFER The target's own experimental annotation is the IBD seed; expected, not circular. Proposed replacements: amino acid transmembrane transport monoatomic cation transmembrane transport Supporting Evidence: PMID:26655471 we reconstituted the purified protein into liposomes and found it to facilitate the transport of small amino acids such as glycine, alanine, valine, and serine, which was confirmed by Pseudomonas growth assays. PMID:19486157 Planar bilayer studies indicated that purified OprG formed cationic-selective channels with a conductance of 500 pS in 1 M KCl |
| GO:0055085 transmembrane transport | IDA PMID:19486157 The major outer membrane protein OprG of Pseudomonas aerugin... | MODIFY | Summary: PseudoCAP IDA from planar bilayer conductance of purified OprG. Sole seed of the GO:0055085 IBD at PTN005107949. Reason: The seed is direct evidence (purified protein forms cation-selective channels), so the claim is sound, but the paper supports the more specific monoatomic cation transmembrane transport; the later amino acid transport data (PMID:26655471) add GO:0003333. Proposed replacements: monoatomic cation transmembrane transport amino acid transmembrane transport Supporting Evidence: PMID:19486157 Planar bilayer studies indicated that purified OprG formed cationic-selective channels with a conductance of 500 pS in 1 M KCl |
| GO:0015288 porin activity | IDA PMID:19486157 The major outer membrane protein OprG of Pseudomonas aerugin... | NEW | Summary: Proposed MF. OprG is an outer membrane beta-barrel that forms channels passing small cations and small amino acids. Reason: GOA has no MF for OprG. Channel formation by the purified protein in planar bilayers and amino acid permeation in reconstituted liposomes show it enables passive transfer of small solutes across the outer membrane through a beta-barrel, which is the definition of porin activity. Supporting Evidence: PMID:19486157 Planar bilayer studies indicated that purified OprG formed cationic-selective channels with a conductance of 500 pS in 1 M KCl PMID:26655471 we reconstituted the purified protein into liposomes and found it to facilitate the transport of small amino acids such as glycine, alanine, valine, and serine, which was confirmed by Pseudomonas growth assays. |
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Download this section (compressed HTML)Q: Do the OmpW-family leaves from eukaryotic genome assemblies (Medicago A0A072TCN1, Nematostella A8DW24) in PTN005107949 represent bacterial contamination, and should they be excluded from PAINT propagation?
Q: How does the anaerobic induction of OprG relate to its amino acid uptake role, and is the cytotoxicity phenotype a consequence of nutrient uptake or of another outer-membrane function?
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